Abstract: An apparatus for making a single face corrugated board having two fluted mediums bonded together at the flute tips has (a) mill roll stands for two mediums and one liner; (b) a carrier roll fluted to support a first fluted medium; (c) a single corrugating roll of diameter not larger than the carrier roll engaging with the carrier roll to corrugate the first fluted medium; (d) a pair of corrugating rolls of diameter no larger than the carrier roll adapted to produce a second fluted medium, the pair being located and driven relative to the carrier roll to enable the first and second fluted mediums to be brought into flute tip to flute tip contact and to be conveyed by the carrier roll, the axes of the corrugating rolls not lying in a plane common with the single corrugating roll or the carrier roll; (e) a first adhesive application station to apply adhesive to one of the fluted mediums prior to the flute tips of the first and second fluted mediums coming into contact; (f) a second adhesive application station t

Abstract: A method and apparatus for determining structural properties of corrugated paperboard in which a sample 21 is held between two axially aligned jaws 13 and 14. The sample is subjected to a twisting force by rotation of one of the jaws and the force and angle of deflection are measured. This gives a relative determination of the boards structural property and is used to assess damage to the corrugated medium during corrugation and subsequent processing steps such as printing. The determination of shear stiffnes in the machine direction is a more reliable measure of board damage than board thickness.

Abstract: Modified apparatus for testing the adhesive strength of the bond between the liner and medium in corrugated paperboard in which a clamp is used having a plate 24 abutting one liner and fingers or prongs 21 holding the medium and liner against the plate 24. The bond between the medium and the other liner is measured by applying a force to a strip bonded to the other liner and measuring the applied force which results in failure of the bond. The sample preparation required is simplified with this design which avoids the use of hooks penetrating the sample.

Abstract: A method and apparatus for manufacturing a corrugated product in which the corrugated mediums are bonded at their flute tips with no intervening liner. A corrugated belt or belts is provided to withdraw the bonded and aligned mediums in a substantially straight line from the pair of corrugating rolls which are synchronised to achieve the alignment and bonding of the flute tips of the two mediums. The corrugated belt provides support and constraint for the bonded mediums until the bond is set or until a liner sheet is bonded to one of the mediums.

Abstract: A structural corrugated paper board for use in forming boxes which incorporates two fluted layers bonded peak to peak enclosed in two outer liners. By increasing board thickness and concentrating strength in the outer liners and eliminating the inner liner between the fluted layers improved edge compression and overall strength per unit weight is improved.